20 lines
767 B
JavaScript
20 lines
767 B
JavaScript
'use strict';
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var GetIntrinsic = require('../GetIntrinsic');
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var $TypeError = GetIntrinsic('%TypeError%');
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var $fromCharCode = GetIntrinsic('%String.fromCharCode%');
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var isLeadingSurrogate = require('../helpers/isLeadingSurrogate');
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var isTrailingSurrogate = require('../helpers/isTrailingSurrogate');
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// https://tc39.es/ecma262/2020/#sec-utf16decodesurrogatepair
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module.exports = function UTF16DecodeSurrogatePair(lead, trail) {
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if (!isLeadingSurrogate(lead) || !isTrailingSurrogate(trail)) {
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throw new $TypeError('Assertion failed: `lead` must be a leading surrogate char code, and `trail` must be a trailing surrogate char code');
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}
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// var cp = (lead - 0xD800) * 0x400 + (trail - 0xDC00) + 0x10000;
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return $fromCharCode(lead) + $fromCharCode(trail);
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};
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